Oil circulates trough the system with the refrigerant. Oil provides lubrication and cools the compressor's moving parts. Because is mixed wit the refrigerant, a refrigerant oil mast to have certain properties. The oil comes in direct contact with hot motor windings in hermetic units. Thous, it must be able to withstand extreme temperatures and be harmless to refrigerants and equipment. Oil in the refrigeration systems is cooled to low temperatures. Yet in must be able to withstand high temperatures at the compressor. It must remain fluid in all parts of the system. The fluidity of an oil-refrigerant mixture is determined by several factors. These include the refrigerant used, temperature, properties of the oil, its solubility in refrigerant, and the solubility of refrigerant in the oil (to keep oil fluid at low temperatures)
-The properties of good refrigerant oil are:
  • Low wax content
  • Good thermal stability
  • Low pour point
  • Low viscosity